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One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
One lung anesthesia
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One lung anesthesia

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  1. ONE LUNG ANESTHESIA DR MAYURI GOLHAR
  2. Initial Preanesthetic Assessment for Thoracic Surgery 1. All patients: Assess exercise tolerance, estimate predicted postoperative FEV1%, discuss postoperative analgesia, discontinue smoking 2. Patients with predicted postoperative FEV1< 40%: DLCO, V/Q scan, VO2 max 3. Cancer patients: consider the “4 Ms”: mass effects, metabolic effects, metastases, medications 4. COPD patients: Arterial blood gas analysis, physiotherapy, bronchodilators 5. Increased renal risk: Measure creatinine and blood urea nitrogen.
  3. Final Preanesthetic Assessment for Thoracic Surgery 1. Review initial assessment and test results. 2. Assess difficulty of lung isolation: examine chest radiograph and computed tomography scan. 3. Assess risk of hypoxemia during one-lung ventilation.
  4. Difficult endobronchial intubation. • At the time of the preoperative visit, there may be historical factors or physical findings that lead to suspicion of difficult endobronchial intubation- previous radiotherapy, infection, prior pulmonary or airway surgery. • In addition, there may be a written bronchoscopy report with detailed description of anatomic features. • The most useful predictor is the plain chest radiograph.
  5. • The anesthesiologist should personally view the chest radiograph before induction of anesthesia and also examine the CT scan. • Distal airway problems not detectable on the plain chest film can sometimes be visualized on the CT scan • Ex-a side-to-side compression of the distal trachea, the so-called saber-sheath trachea, can cause obstruction of the tracheal lumen of a left- sided DLT during ventilation of the dependent lung for a left thoracotomy. • Similarly, extrinsic compression or intraluminal obstruction of a mainstem bronchus that can interfere with endobronchial tube placement may be evident only on CT .
  6. The left thorax showing tumor compressing the trachea and pl effusion.
  7. Factors That Correlate with an Increased Risk of Desaturation during One-Lung Ventilation • High percentage of ventilation or perfusion to the operative lung on preoperative scan • Poor PaO2 during two-lung ventilation, particularly in the lateral position intraoperatively • Right-sided thoracotomy • Normal preoperative spirometry (FEV1 or FVC) or restrictive lung disease • Supine position during one-lung ventilation
  8. INDICATIONS OF OLV • ABSOLUTE- 1. To prevent spillage or contamination 2. Control of distribution of ventilation in BPF, surgical opening of major bronchus, cyst, bulla. 3. Unilateral bronchopulmonary lavage in pul arteriolar proteinosis
  9. • RELATIVE- 1. Pneumonectomy 2. Lobectomy 3. Thoracic aortic aneurysm 4. Minimally invasive CABG 5. Upper oesophagical resection 6. Thoracoscopic procedure 7. Thoracic spine surg
  10. MONITERING • NON-INVASIVE- PULSE OXIMETRY, CAPNOMETRY • INVASIVE- ARTERIAL CVP PA
  11. INTRA-OPERATIVE MONITERING • A majority of these operations are major procedures of moderate duration (2-4 hours) and performed in the lateral position with the hemithorax open. • Thus, consideration for monitoring and maintenance of body temperature and fluid volume should be given to all of these cases. • Because surgery is usually performed in the lateral position, monitors will initially be placed with the patient in the supine position and have to be rechecked and often repositioned after the patient is turned. • It is often difficult to add additional monitoring, after the case is started if complications arise. Choice of monitoring should be guided by a knowledge of which complications are likely to occur.
  12. Intraoperative Complications That Occur with Increased Frequency during Thoracotomy
  13. OXYGENATION • SPO2 AND PaO2 • The PaO2 value offers a more useful estimate • A patient with a two-lung ventilation PaO2 greater than 400 mm Hg with an FIO2 of 1.0 (or an equivalent PaO2/FIO2 ratio) is unlikely to desaturate during OLV whereas a patient with a PaO2 of 200 mm Hg is prone to desaturate during OLV, although both may have SpO2 values of 99% to 100%. • The rapidity of the fall in PaO2 after the onset of OLV is an indicator of the risk of subsequent desaturation. • Measure PaO2 by arterial blood gas analysis before OLV and 20 minutes after the start of OLV. • During hypoxemia, SpO2 sensor malpositioning can cause significant underestimation of saturation.
  14. CAPNOMETRY • The end-tidal CO2 (PETCO2) is a less reliable indicator of the PaCO2 during OLV than during two-lung ventilation. • The PETCO2 reflects the lung perfusion and cardiac output. • As the patient is turned to the lateral position the PETCO2 of the nondependent lung will fall 1. reflecting increased perfusion of the dependent lung 2. increased dead space of the nondependent lung. 3. The fractional excretion of CO2 will be higher from the nondependent lung -increased fractional ventilation of this lung.
  15. • At the onset of OLV -the PETCO2 of the dependent lung will usually fall transiently as all the minute ventilation is transferred to this lung. • The PETCO2 will then rise as the fractional perfusion is increased to this dependent lung by collapse and pulmonary vasoconstriction of the nonventilated lung. • However, severe (>5 mm Hg) or prolonged falls in PETCO2 can indicate an maldistribution of perfusion between ventilated and nonventilated lungs and may be an early warning of a patient who will subsequently experience desaturation during OLV
  16. ARTERIAL LINE • INDICATED-severe hypotension from surgical compression of the heart or great vessels. • placement of a radial artery catheter can be in either the dependent or the nondependent arm
  17. CENTRAL VENOUS PRESSURE • The CVP is a useful monitor postoperatively, particularly for cases in which fluid management is critical (e.g., pneumonectomies). • PLACED-pneumonectomy patients but not for lesser resections unless there is significant other concurrent illness. • For lobectomies that unforeseeably become pneumonectomies a CVP catheter is placed at the end of the operation. • Our choice is to use the right internal jugular vein to minimize the risk of pneumothorax for CVP access unless there is a contraindication.
  18. PULMONARY ARTERY CATHETER • When left-sided pulmonary artery catheter placement is required it can be achieved by floating the catheter into the pulmonary artery when the patient is in the right lateral position. • The surgeon can confirm the placement of the pulmonary artery catheter once the chest is open. • It is extremely important to remember that a pulmonary artery catheter ipsilateral to the side of surgery must be withdrawn before vascular clamping or it could be transected. • Complications from the use of pulmonary artery catheters including arrhythmias, hemorrhage, pulmonary infarction. • If a pulmonary artery catheter is in the nonventilated lung it frequently becomes accidentally wedged without balloon inflation as the lung collapses. • Used only in certain specific cases, such as patients with major coexisting disease (e.g., cardiac, renal) or having particularly extensive procedures (e.g., extrapleural pneumonectomy).
  19. FIBEROPTIC BRONCHOSCOPIC MONITERING • Placement of DLTs or blockers should be performed with fiberoptic bronchoscopic guidance and should be reconfirmed after placing the patient in the surgical position because a large number of these tubes/blockers migrate during repositioning of the patient
  20. CONTINOUS SPIROMETRY • The side-stream spirometry -continuously monitors 1. inspiratory and expiratory volumes, pressures, 2. flow interactions during one-lung anesthesia. 3. gives early warning of accidental changes in the intraoperative position of a DLT 4. the development of auto-PEEP, can also be seen on the flow-volume loop.
  21. TEE The American Society of Anesthesiologists and Society of Cardiovascular Anesthesiologists CATEGORY 1 CATEGORY 2 CATEGORY 3 CARDIAC/ GREAT VESSELS INVOLVEMENT BY INTRATHORACIC TUMORS HEMODYNAMIC INSTABILITY PULMONARY THROMBOENDARTERCTOMY RIGHT VENTRICULAR FUNCTIONS CARDIAC TAMPONADE AIR EMBOLI PERICARDIAL EFFUSSION LUNG TRANSPLANT THORACIC TRAUMA
  22. LUNG ISOLATION TECHNIQUES • Double-lumen tube 1. Direct laryngoscopy 2. Via tube exchanger 3. Fiberoptically. • ADVANTAGES-Quickest to place successfully Repositioning rarely required Bronchoscopy to isolated lung Suction to isolated lung CPAP easily added Can alternate OLV to either lung easily Placement still possible if bronchoscopy not available • DISADVANTAGE-Size selection more difficult Difficult to place in patients with difficult airways or abnormal tracheas Not optimal for postoperative ventilation Potential laryngeal trauma Potential bronchial trauma
  23. • Bronchial blockers (BB)- Arndt ,Cohen ,Fuji. • ADVANTAGE-Size selection rarely an issue Easily added to regular ETT Allows ventilation during placement Easier placement in patients with difficult airways and in children Postoperative two-lung ventilation by withdrawing blocker Selective lobar lung isolation possible CPAP to isolated lung possible . • DISADVANTAGE-More time needed for positioning Repositioning needed more often Bronchoscope essential for positioning Nonoptimal right lung isolation due to RUL anatomy Bronchoscopy to isolated lung impossible Minimal suction to isolated lung Difficult to alternate OLV to either lung
  24. • Univent tube • ADVANTAGE-Same as BBs Less repositioning compared with BBs. • DISADVANTAGE-Same as for BBs ETT portion has higher air flow resistance than regular ETT ETT portion has larger diameter than regular ETT
  25. • Endobronchial tube. • ADVANATGE-Like regular ETTs, easier placement in patients with difficult airways Longer than regular ETT Short cuff designed for lung isolation . • DISADVANTGE-Bronchoscopy necessary for placement Does not allow for bronchoscopy, suctioning or CPAP to isolated lung Difficult right lung OLV
  26. ENDOBRONCHIAL TUBE
  27. DOUBLE LUMEN TUBE • 1950-The use of the Carlens design of DLT for lung surgery was a landmark in the development of thoracic However, the Carlens tube had a high flow resistance owing to the narrow lumens and also the carinal hook was difficult to pass through the glottis in some patients. • In the 1960s, Robertshaw introduced design modifications for separate left- and right-sided DLTs, removing the carinal hook and using larger lumens. • In the 1980s, manufacturers introduced disposable DLTs made of polyvinyl chloride based on the design of the Robertshaw DLT. • Among other subsequent improvements is the inclusion of radiographic markers near the endotracheal and endobronchial cuffs and a radiographic marker surrounding the ventilation slot for the right upper lobe bronchus for the right-sided DLT version. • Bright blue, low-volume, low-pressure endobronchial cuffs are incorporated for easier visualization during fiberoptic bronchoscopy.
  28. CARLENS TUBE
  29. ROBERTSHAW TUBE • 2D shaped lumen • Rt-bronchial lumen at 20 & lt- 40 • 2ends- tracheal/ bronchial • 2curves- proximal- oropharyngeal, distal- bronchial • 2cuff-bronchial/ tracheal • Malleable stylet &suction catheter
  30. SIZE SELECTION • A left-sided DLT should have a bronchial tip 1 to 2 mm smaller than the patient's left bronchus diameter - allow for the space occupied by the deflated bronchial cuff. • Chest radiographs and CT scans are valuable tools for selection of proper DLT size.
  31. SIZE SELECTION ACCORDING TO SEX AND HT SEX HEIGHT (CM) Fr FEMALES <160 35 FEMALES >160 37 MALES <170 39 MALES > 170 41 AVAILABLE IN SIZES- 26, 28,32, 35,37,39,41
  32. Normal anatomy
  33. METHOD OF INSERTION • The DLT is passed with direct laryngoscopy beyond the vocal cords. • The DLT should pass the glottis without any resistance.
  34. • The DLT is rotated 90 degrees to the left (counterclockwise
  35. • The optimal depth of insertion -the patient's height in average-sized adults. • In adults, depth, measured at the teeth, for a properly positioned DLT will be approximately 12 + (patient height/10). • An inadvertently deep insertion of a DLT can lead to serious complications, including rupture of the left mainstem bronchus.
  36. • The right mainstem bronchus is shorter than the left bronchus • the right upper lobe bronchus originates at a distance of 1.5 to 2 cm from the carina, so the right endobronchial intubation can account for obstruction of the orifice of the right upper lobe bronchus. • The right-sided DLT incorporates a modified cuff, or slot, on the endobronchial side that allows ventilation for the right upper lobe. • Indications for rt sided DLT insertion- 1. Distorted Anatomy of the Entrance of Left Mainstem Bronchus External or 2. intraluminal tumor compression 3. Descending thoracic aortic aneurysm 4. Site of Surgery Involving the Left Mainstem Bronchus 5. Left lung transplantation 6. Left-sided tracheobronchial disruption 7. Left-sided pneumonectomy 8. Left-sided sleeve resection
  37. Positioning of the DLT • Auscultation and bronchoscopy should both be used • Fiberoptic bronchoscopy is performed first through the tracheal lumen to ensure that the endobronchial portion of the DLT is in the l bronchus and that there is no bronchial cuff herniation over the carina after inflation. • Through the tracheal view, the blue endobronchial cuff ideally should be seen approximately 5 mm below the tracheal carina in the left bronchus. • identify the takeoff of the right upper lobe bronchus through the tracheal view. • Going inside this right upper lobe with the bronchoscope should reveal three orifices (apical, anterior, and posterior).
  38. A “three-step” method to confirm position of a left DLT by auscultation 1. During bilateral ventilation, the tracheal cuff is inflated to the minimal volume that seals the air leak at the glottis. Auscultate to confirm bilateral ventilation
  39. • The tracheal lumen of the DLT is clamped proximally and the port distal to the clamp opened. • During ventilation via the bronchial lumen the bronchial cuff is inflated to the minimal volume that seals the air leak from the open tracheal lumen port. • Auscultate to confirm correct unilateral ventilation
  40. • 3. The tracheal lumen clamp is released and the port closed. Auscultate to confirm resumption of bilateral breath sounds
  41. PROBLEMS -DLT • malposition and airway trauma. • A malpositioned DLT will fail to allow collapse of the lung, causing gas trapping during positive-pressure ventilation, or it may partially collapse the ventilated or dependent lung, producing hypoxemia. • cause of malposition - cuff overinflation, surgical manipulation of the bronchus, or extension of the head and neck during or after patient positioning. If a DLT is in the optimal position, but lung deflation is not completely achieved, a suction catheter should be passed to the side where lung collapse is supposed to occur. This suction will expedite lung deflation.
  42. • Airway trauma • rupture of the membranous part of the trachea or the bronchus • Airway trauma -oversized DLT or when an undersized DLT migrates distally into the bronchus . • Airway damage -air leak, subcutaneous emphysema, massive airway bleeding into the lumen of the DLT, or protrusion of the endotracheal or endobronchial cuffs into the surgical field. • Tension pneumothorax in the dependent, ventilated, lung during OLV
  43. DIFFICULT AIRWAY AND OLV • carcinoma of the pharynx, usually in the epiglottic area. • previous radiation therapy on the neck • previous airway surgery, such as hemi-mandibulectomy or hemiglossectomy. • descending thoracic aortic aneurysm . • an intraluminal or extraluminal tumor near the tracheobronchial bifurcation. • SLT placed orally with the aid of a flexible fiberoptic bronchoscope, after appropriate airway anesthesia is achieved. • this may be performed after induction of anesthesia with a bronchoscope or with a videolaryngoscope. • Once the SLT is in place, an independent bronchial blocker can be passed. • If the patient requires OLV and cannot be intubated orally, an awake nasotracheal intubation can be performed with an SLT and, once the airway is established, then a bronchial blocker can be passed.
  44. Other method • intubate the patient's trachea with an SLT; then a tube-exchange technique can be used to replace the existing SLT for a DLT after general anesthesia is induced • For a DLT the exchange catheter should be at least 83 cm. A 14-Fr exchange catheter can be used for 41-Fr and 39-Fr DLTs; for 37-Fr or 35-Fr DLTs an 11-Fr exchange catheter is used. • A sniffing position facilitates tube exchange. After the exchange catheter is lubricated, it is advanced through an SLT. • The catheter should not be inserted deeper than 24 cm at the lips to avoid accidental rupture or laceration of the trachea or bronchi. • After cuff deflation, the SLT is withdrawn. Then the endobronchial lumen of the DLT is advanced over the exchange catheter. • Proper final position of the DLT is then achieved with auscultation and bronchoscopy.
  45. Lung-Isolation Techniques in Patients with a Tracheostomy in Place • (1) insertion of an SLT followed by an independent bronchial blocker • (2) the use of a disposable cuffed tracheostomy cannula with an independent bronchial blocker passed coaxially • (3) replacement of the tracheostomy cannula with a specially designed short DLT such as the Naruke DLT, which is made for use in tracheostomized patients • (4) placement of a small DLT through the tracheostomy stoma • (5) if possible, oral access to the airway for standard placement of a DLT or blocker
  46. POSITIONING • It is useful to make an initial “head-to-toe” survey of the patient after induction and intubation, checking oxygenation, ventilation, hemodynamics, lines, monitors, and potential nerve injuries. • Certainly the patient's head, neck, and endobronchial tube should be turned “en bloc” with the patient's thoracolumbar spine. • Neurovascular Complications - • The brachial plexus -The patient should be positioned with padding under the dependent thorax to keep the weight of the upper body off the dependent arm brachial plexus. • Vascular compression of the nondependent arm is possible-monitor pulse oximetry in the nondependent hand to observe this. • The arm should not be abducted beyond 90 degrees • Anterior flexion of the arm at the shoulder (circumduction) across the chest or lateral flexion of the neck toward the opposite side can cause a traction injury of the suprascapular nerve. • This can cause post-thoracotomy shoulder pain.
  47. Correct position • The dependent leg - slightly flexed with padding under the knee to protect the peroneal nerve. • The nondependent leg is placed in a neutral extended position and padding placed between it and the dependent leg. • Excessively tight strapping at the hip level can compress the sciatic nerve of the nondependent leg. • Other sites liable injury -are the dependent ear pinna and eye.
  48. OLV PHYSIOLOGY • Lateral position, awake, breathing spontaneously, chest closed • The distribution of blood flow and ventilation is similar to that in the upright position, but turned by 90 degrees . • Blood flow and ventilation to the dependent lung are significantly greater than to the nondependent lung. • Good V/Q matching at the level of the dependent lung results in adequate oxygenation in the awake patient who is breathing spontaneously. • During spontaneous ventilation, the conserved ability of the dependent diaphragm to contract results in an adequate distribution of VT to the dependent lung. • Because most of the perfusion is to the dependent lung, the V/Q matching in this position is maintained similar to that in the upright position.
  49. • Lateral position, awake, breathing spontaneously, chest open • Two complications can arise – 1. The first is mediastinal shift, usually occurring during inspiration negative pressure in the intact hemithorax the mediastinum to move vertically downward and push into the dependent hemithorax. The mediastinal shift can create circulatory and reflex changes that may result in a clinical picture similar to that of shock and respiratory distress.
  50. 2. paradoxical breathing . During inspiration, the relatively negative pressure in the intact hemithorax compared with atmospheric pressure in the open hemithorax movement of air from the nondependent lung into the dependent lung. The opposite occurs during expiration. This gas movement reversal from one lung to the other represents wasted ventilation and can compromise the adequacy of gas exchange. Positive-pressure ventilation or adequate sealing of the open chest eliminates paradoxical breathing
  51. • Lateral position, anesthetized, breathing spontaneously, chest closed • VT enters the nondependent lung, and this results in a significant [V]/[Q] mismatch. • reduction in FRC. • the cephalad displacement of the dependent diaphragm by the abdominal contents is more pronounced and is increased by paralysis. • the mediastinal structures pressing on the dependent lung or poor positioning of the dependent side on the operating table prevents the lung from expanding properly. • The nondependent lung moves to a steeper position on the compliance curve and receives most of the VT, whereas the dependent lung is on the flat (noncompliant) part of the curve
  52. Lateral position, anesthetized, paralyzed, chest open • During paralysis and positive-pressure ventilation, diaphragmatic displacement is maximal over the nondependent lung, where there is the least amount of resistance to diaphragmatic movement • This further compromises the ventilation to the dependent lung and increases the V/Q mismatch.
  53. One-lung ventilation, anesthetized, paralyzed, chest open • During two-lung ventilation in the lateral position, the mean blood flow to the nondependent lung is assumed to be 40% of cardiac output, • whereas 60% of cardiac output goes to the dependent lung Normally, • venous admixture (shunt) in the lateral position is 10% of cardiac output and is equally divided as 5% in each lung. • Therefore, the average percentage of cardiac output participating in gas exchange is 35% in the nondependent lung and 55% in the dependent lung.
  54. • OLV creates an obligatory right-to-left transpulmonary shunt because the V/Q ratio of that lung is zero. • active HPV, blood flow to the nondependent hypoxic lung will be decreased by 50% and therefore is (35/2) = 17.5%. To this, 5% must be added, which is the obligatory shunt through the nondependent lung. The shunt through the nondependent lung is therefore 22.5% • Together with the 5% shunt in the dependent lung, total shunt during OLV is 22.5% + 5% = 27.5%. This results in a Pao2 of approximately 150 mm Hg (FIO2 = 1.0).
  55. • Because 72.5% of the perfusion is directed to the dependent lung during OLV, the matching of ventilation in this lung is important for adequate gas exchange. • There are several reasons for reduction in FRC, 1. including general anesthesia, paralysis, 2. pressure from abdominal contents, 3. compression by the weight of mediastinal structures, 4. suboptimal positioning 5. atelectasis, 6. accumulation of secretions 7. formation of a fluid transudate in the dependent lung. All these create a low V/Q ratio and a large P(A-a)o2 gradient
  56. Anesthetic Management • Fluid Management hydrostatic effects increased shunting subsequently lead to pulmonary edema of the dependent lung. • judicious fluid administration. • Intravenous fluids are administered to replace volume deficits and for maintenance only during lung resection anesthesia. • No volume is given for theoretical “third space” losses during thoracotomy • The commonly accepted dictum is “don't drown the down lung.”
  57. 1. Total positive fluid balance in the first 24-hour perioperative period should not exceed 20 mL/kg. 2. For an average adult patient, crystalloid administration should be limited to < 3 L in the first 24 hours. 3. There should be no fluid administration for third space fluid losses during pulmonary resection. 4. Urine output > 0.5 mL/kg/hr is unnecessary. 5. If increased tissue perfusion is needed postoperatively, it is preferable to use invasive monitoring and inotropes rather than to cause fluid overload.
  58. N2O AND TEMPERATURE • Nitrous oxide/oxygen (N2O/O2) mixtures are more prone to cause atelectasis. • The rate of uptake of an N2O/O2 mixture from an unventilated lung exceeds that of pure oxygen. • Nitrous oxide also tends to increase pulmonary artery pressures in patients who have pulmonary hypertension. • N2O inhibits HPV ,and N2O is contraindicated in patients with blebs or bullae. For these reasons N2O is usually avoided during thoracic anesthesia • heat loss from the open hemithorax. • HPV, are inhibited during hypothermia. • Increasing the ambient room temperature, fluid warmers, and the use of lower- or upper-body forced-air patient warmers methods to prevent inadvertent intraoperative hypothermia.
  59. HYPOXIC PULMONARY VASOCONSTRICTION • HPV -governs the redistribution of blood flow during OLV. • It decreases the blood flow to the nonventilated lung by 50%. • The stimulus is alveolar oxygen tension (PAO2), which stimulates precapillary vasoconstriction redistributing pulmonary blood flow away from hypoxemic lung regions via a pathway involving NO and/or cyclooxygenase synthesis inhibition.[ • HPV starts over the first 30 minutes and then a slower increase to a maximal response at approximately 2 hours.
  60. Factors affecting HPV • The surgical trauma • Surgery may oppose HPV by release of vasoactive metabolites. • HPV is decreased by vasodilators such as nitroglycerin and nitroprusside • Thoracic epidural sympathetic blockade probably has little or no direct effect on HPV
  61. CHOICE OF ANESTHETICS • All of the volatile anesthetics inhibit HPV in a dose-dependent fashion. • The older agents were potent inhibitors of HPV • In doses less than or equal to 1 MAC, the modern volatile anesthetics (isoflurane, sevoflurane, and desflurane) are weak, and equipotent, inhibitors of HPV.
  62. VENTILATION STRATERGIES • Tidal volume- 5-6 mL/kg • Peak airway pressure < 35 cm H2O • Plateau airway pressure < 25 cm H2O. • Positive end-expiratory pressure 5 cm H2O Patients with COPD: no added PEEP. • Respiratory rate 12 breaths/min & Maintain normal PaCO2. • Mode Volume or pressure controlled .Pressure control for patients at risk of lung injury (e.g., bullae, pneumonectomy, post lung transplantation)
  63. THERAPIES OF HYPOXEMIA • During OLV there will be a fall in arterial oxygenation by 20 to 30 minutes after the initiation of OLV • then the saturation will stabilize or may rise slightly as HPV increases over the next 2 hours. • A majority of patients who desaturate do so quickly and within the first 10 minutes of OLV. Hypoxemia during OLV responds readily to treatment in the vast majority of cases.
  64. 1. Resume two-lung ventilation. Reinflate the nonventilated lung and deflate the bronchial cuff of the double lumen tube or the bronchial blocker. 2. Increase FIO2. Ensure that the delivered FIO2 is 1.0 3. Recheck the position of the DLT or bronchial blocker. Ensure that there is no lobar obstruction in the ventilated lung.
  65. • 4. Check the patient's hemodynamics to ensure that there has been no decrease in cardiac output Treat the fall in cardiac output as indicated (e.g., inotropes/vasopressors if due to thoracic epidural sympathetic blockade). • Stop administration of vasodilators, and decrease MAC of volatile anesthetics to less than or equal to 1 MAC.
  66. • CPAP- 5-10cms of H2O can be applied to the non- dependant lung,this allows some gas exchange in the non-dependant lung. • PEEP-5-10cms of H2O can be applied to the dependant lung, this shifts it to the more complaint part of the pressure volume curve. • CPAP &PEEP can be gradually in increments of 5cms as long the pts hemodynamic status remains stable.
  67. PAIN MANAGEMENT • Thoracic epidural –gold std • Local anesthetic are given via a patient control device • Parenteral opioids- via pt control analgesia & are considered to be superior to IM/Ivopioids • Paravertebral blocks- intercostal nerves, unilateral analgesia, lesser side effects. • Intrathecal oipoids- preservative free morphine can be injected into the SAB at lumbar level, causes rostral spread, dose-5-20ug/kg(24hr). • Intercostal nerve blocks- blocked above & below the surgical incision but it is short acting.
  68. POST-OP COMPLICATIONS Cvs- arrhythmias,Rt ventricular failure,Cardiac herniation,Hemorrhage Pulmonary- pul edema, respiratory insufficiency, pul torsion. Pneumonectomy space- BP fistula, empyema Neurological- RLN, vagus and phrenic nerve injuries
  69. THANK YOU..

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